ESTRO 36 Abstract Book

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S869 ESTRO 36
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Conclusion
We independently validated a radiomic model to
distinguish between HPV+ and HPV- OPSCC patients, using
standard pre-treatment CT imaging. These results show
the potential for a novel quantitative Radiomic biomarker
of HPV status to facilitate personalized treatment
selection and reinforce the hypothesis that genetic
information can be inferred from standard medical
images.
EP-1609 Tolerance doses for detailed late effects after
prostate cancer radiotherapy – a post-QUANTEC review
C. Olsson 1, M. Thor 2, J.O. Deasy 2
1 University of Gothenburg, Regionalt Cancercentrum RCC
väst, Gothenburg, Sweden
2 Memorial Sloan Kettering Cancer Center, Medical
Physics, New York, USA
Purpose or Objective
To review tolerance doses for normal tissue toxicity
following external beam radiotherapy (EBRT) for prostate
cancer in the post-QUANTEC era with a special emphasis
on detailed late effects beyond rectal bleeding, and to
identify corresponding relationships following
brachytherapy (BT).
Material and Methods
The electronic database PubMed was scrutinized for full-
text articles published in English since the publication of
the QUANTEC reviews (Jan 1 st 2010; EBRT only), and since
the Emami study (Jan 1st 1992; including BT). Studies
qualifying for inclusion were randomized controlled/case-
control/cohort studies with specific non-aggregated
symptom assessments, follow-up >3 months, >20 patients,
primary standard treatments for localized prostate cancer
with dose-volume based data. Two investigators
independently assessed study quality according to eight
criteria1 and an additional study-specific criterion
incorporating dose-association complexity. Quantitative
synthesis for sufficiently homogenous studies was
performed for each treatment modality with dose cut
points converted into equivalent doses in 2-Gy fractions
(α/β=3 Gy). If not explicitly reported, thresholds were
derived from suggested models and estimated at a risk
level of 10%. The review was registered at PROSPERO
International prospective register of systematic reviews
on July 12, 2016.
1 Agency for Healthcare research and quality, US
department of Health in Human services;
998/MethodsGuideforCERs_Viswanathan_IndividualStudie
s.pdf
Results
The search strategy resulted in 1095 abstracts (Figure 1)
of which 44 studies fulfilled the inclusion criteria and were
available in full text (one study was excluded based on
study quality criteria). The review is expected to include
syntheses of dose-response relationships for seven gastro-
intestinal symptoms
(bleeding/diarrhea/frequency/incontinence/pain/proctit
is/urgency: n=18/3/4/10/3/4/4), three genitourinary
symptoms (hematuria/incontinence/obstruction:
n=4/4/3), and one sexual dysfunction symptom (erectile
dysfunction: n=3) following EBRT. The corresponding
figures for BT±EBRT will be two (bleeding/urgency:
n=6/2), four (incontinence/obstruction/pain/stricture:
n=4/2/3/2), and one symptom (erectile dysfunction: n=2).
Results for diarrhea, stool frequency, and defecation
urgency following EBRT are presented in Figure 2. Dose
cut points for the rectum and anal canal/sphincter region
generally followed the same linear slope for
diarrhea/defecation urgency across studies; for stool
frequency they were less consistent.
Conclusion
Our review demonstrates continuous and innovative
activity in the field of late toxicity after prostate cancer